Dead-weight gage-tester.



F. H. HOPKINS.

DEAD WEIGHT GAGE TESTER.

APPLlcATloN FILED 1AN.22.1913.

1,154,01. Parentedsept. 21, 1915.

CDLUMBIA PLANODRAPH C0.,WASHINGTON. D. c.

unir @rre einer re.

FRANK H. HOPKINS, OF SOIVIERVILLE, MASSACHUSETTS,

ASSIGNOR TO AMERICAN STEAM GAUGE AND VALVE MANUFACTURING COMPANY, OF BOSTGN, MASSACHU- SETTS, A CR-PORATION GF NEW JERSEY.

DEAD-WEIGIT GAGE-TESTER.

Specification of Letters Patent.

Patented Sept. 21, 1915.

Application filed January 22, 1913. Serial No. 743,521.

tirely incompressible tluid, such as water or other freely flowing lioluid, 4which is adapt-y ed to cuter the pressure-measuring element of the gage, and upon which the weights are caused to press. Heretofore gage testers oil this type, which are known as dead wcght testers7 because weights are employed to act directly upon the transmitting Suid, haye been impracticable for testing up to very high pressure, on account of the v.'ery great size land bulk of the weights required to produce such high pressures. Y

lt is the object ot my invention to produce a tester in which pressures may be developed through the direct action of weights to any degree from a tract-ion ot a pound up to twenty-five thousand or more pounds, with the use ot' weights of moderate vsize and comparatircly few in number, and therefore without requiring excessively large weights or a great number of them. This object is accomplished by compounding or multiplyl the fluid pressures produced Aby the action of the weights so that at the point where such pressures are transmitted to the gage, they are greatly multiplied inamount or intensity, and by providing means whereby the intermediate pressure multiplying members may be temporarily discontinued trom operation so that lower pressures may be transmitted from the -weight to' the gage. iin apparatus by which this 'ob]ect is accomplished, and in which my invention is embodied is illustrated in the accompanying drawings and described iii detail'in the tollowing specification. rlhe particular apparatusv is not intended to represent vthe only possible embodiment ot the invention, however, but is shown and described .in Vorder to explain the principles of' 'the invention and as'being illustrative oi one particular embodiment of such principles in concrete form.

In the drawings, Figure l is a front ele- `"ation of the tester showing a gage connected thereto for testing. Fig. 2 is a side elevation as seen ltrom the right of Fig. l.

Fig. 3 is a vertical section in a plane parallel to that in which Fig. l is projected. Fig. 4 is a detail sectional view on a larger scale or" the part of the tester in which the weights-more directly act. Fig. 5 is a detail sectional view ot the connection for the gage. Fig. G is a vertical sectional view of the chamber in which the manually operated plunger which is used for putting the tester into operation is contained, said gure showing 'the plunger in rsuch chamber. F ig. 7 is a sectional view of a needle valve constituting a detail of the tester. Fig. 8 is a sectional view similar to Fig. showing a form of weight and plunger used in substi-` a nipple 3 to which the gage el to be testedv is connected by a connection which I will presently describe in detail. Posts 5, of

which there are conveniently three rise from the base l and support the base 6 of a second or intermediate cylinder 7. Such second cylinder is directly over the high pressure cylinder 2, and the posts 5 are so spaced as to support the same in a sufficiently secure manner. Secured to and rising from the top of the second cylinder 7 is a thirdv cylinder 8 vwhich may be called the top cylinder or primary cylinder, and contains a piston provided with a table 9 on which weights 10 may be removably placed. Referring to Fig. 3 which shows the internal chambers of the various cylinders and the connecting passages, and referring alsoA to Fig. 4: *which shows the top cylinder on a larger scale, it will b e 'seen that said Fig 9 is a detail Yioo topv cylinder has a nipple 1l which is screwed r into'the cylinder 7, and that it contains a chamber or passage 12 in its lower portion' opening into said cylinder 7, and that it has a larger' chamber 13 in its upper part, into which: the chamber 12 opens. The top of said cylinder S is closed by a removable cap 14 which has an internally threaded flange 15 engaging external threads at the end of the cylinder. The piston heretofore lmentioned as carrying the weight table 9 Ais shown in Figs. 3 and 4,' and is made at its lower end as a piston 16 fitting the chamber l2. Its upper portion which passes through the enlarged chamber 13 maybe larger than the piston portion 16, as shown, and is equipped with a stop collar 17 fitting. freely f in the chamber 13, the purpose of which collar is to prevent thepiston from leaving the chamber 12when it is raised by displacement of the transmission fluid through the application of pressure as hereinafter described. Said stop collar bystriking the cap 14 prevents removal of the piston. The stem ofthe piston passes through .the cap 14, through which it is adapted to slide endwise freely, and is threaded at 13 to enable the table 9 to be secured upon it. When the cap 14 is rein'ovedthe top cylinder is open at the upper end,where upon the piston 16 maybe removed for the purpose of substituting an- Y other piston, as I shall presently. describe.

The second or intermediate cylinder has a chamber 19 in which. is contained a piston 20, such piston extending below the base of the cylinder 7 and resting on a piston 21 in the chamber 22 `in the high pressure or first Acylinder 2. It will-be noted that the piston 21 and chamber 22 are of much smaller diameter than the piston 2Q and chamber 19. This diiference in diameter is provided E in order that a known fluid Dressureon the piston 2O may be employed to produceramany times great-er pressure in thechamber 22. On the piston' 20 'there is secured a weight 23 of known value, which is also of symmetrical form with respect to the axis zofthe piston and is equipped with teeth 24 for a purpose which I willpresently describe. This weight is centrally apertured and placed on the reduced lower end of piston 20, being secured thereon and .held against ashoulder 25 by a nut 26 screwed on the piston below the weight. Projecting fromfthefunder side of the weight 23 is a pin 2S Awhich crosses. a dogv29jsecured to and projecting from the piston 21, the purposecf which will be presently described.

llVhile it is not material to the. invention howthe several cylinders are made, that is, whether or not they are integrally connected, I may state that for practical reasons I prefer Vto make them all structurally independent 4,of Yone another and also of the base 1 the, higlrpressure cylinder being provided with a nipple which is threaded intothe base as, shown in Fig. 3, the intermediate pist'nbeing supported. by posts 5 rising from the base as shown, and the primary cylinder being detachably connected to the intermediate v'tiylirider- The 'chamber 22 opens into a transverse chamber in the basel from which vextend a passage 3l and a passage 32, the former extending through the gage connection '1'ii`pple3and the latter extending into comi'iiiiiiication with a by-pass 33. Such bypass runs from a three-way cock 34, connecting with a passage in the side of the cylind-er 7 communicating with the chamber 19, to a needle valve casing 36 which is screwed into the` base inthe external orifice ofthe passage Said needle valve casing andthe/contained .valve are shown in detail in Fig. 7. The casing has a threaded nipple 37 at Aone end, and ,atits opposite end has a threaded opening 33 to receive the coupling of theby-pass pipe 33. A passage 39 runs throughtheneedle valve casing andis offset at Van interior point so as to provide1 a valve seat 40 witl'rwhich a needlev valve 41 co-acts. Said needle valvel passes through a stuiiing box `consisting of a lgland 42 screwed into the side of the casing and through which the stem of the needle valve is threaded. Surrounding vthe `needle valve is a wa'sher43 which bears against a shoulder between the needle .valve passage and the gland opening,.,and betweenwhich and the end'ofv the gland there is a packingv44 which is 'com-pressed by the -gla'nd 'against the needle valve Von all sides. The external end of the needle valve stern iseprovided with a hand wheel 45 or equivalent handle by which it may be rotatedin being closed or opened. In the construction of .the needle valve and its packing; have produced a new and improved construction which allows the valve to be packed securely sof as to prevent leakage of ,fluid at very high pressures and beingat the same time small and compact.

The threeway cock 3 4 previously mentioned has yfth'ree distinct openings into its casing, one being from the chamber 19, the other being to Ythe by-pass pipe 33 and the third being to a .tank or reservoir 46 which contains a supply of the pressure transmitting fluid. By suitably turning the cock, which has *a handle 47 shown in Fig. 1, the chamber r19 can be put into communication either .with `the tank 46 or with the bypass 33, vor it may be entirely closed, and the tank 46 may be vput into communication with the chambers and passages contained in the base 1 'when the cock is suitably polsi-V tioned andlthe needle valve is opened.

In the chamber 30of the base there is contained 'a pressure plunger 48 formed as a screw s o that it may be advanced with great powerl by the application of manual force. This screw plunger has a stop collar 49 'on the end withinthe chamber 30 to prevent the plunger from being withdrawn from the IIC ist.'

'the flange 5T.

chamber and passes through a gland in the open end of chamber 30 the side of the base7 with which gland it has a threaded engagement. ySecured to the outer end oi the screw plunger there is a collar 5l having lever arms The gland and packing 'for the screw plunger are of the same character as the gland and packing for the needle Valve. rllhere is a washer 53 surrounding the screw plunger loosely and bearing against a shoulder 5l in the chamber 30, while also surrounding the plunger and compressed between the gland and the washer is a quantity of packing material The connection by which the gage to be tested is detL chably connected to the tester is best shown in enlarged sectional view in Fig. 5. tube 5G has a tapered threaded end which is screwed into a relier" valve casing G2, pr vided to drain the gage, which in turn is screwed into the base in a threaded socket forming the external oriice of the passage 31. This tube has on its end a flange 57 which retains a nut 58 rotatably mounted on the tube. Said nut is tormedas the hub of a hand wheel 59 and has at oneY end of its threaded internal opening a lipl GO which underlies the flange A spring u31 surrounds the tube 5G and abuts againstv the relief valve casing 62 which contains the needle valve 53, said spring also pressing against the nut and holdin@` its li a SO ua to a M n 1 the flange oi. A block 6-1 winch has a threaded recess adapted to receive the threaded nipple of the gage, has a neck (56 which is engaged with the threads in the nut 5S, and a lock nut 58a is also threaded upon said neck 66 and is crowded against the end of the nut 5S or hand wheel hub. Rr tube 6? of hard material, suitably steel, is contained in the upper end of the tube 5G, and passes through the block (34.- to a point somewhat beyond the bottoni of the recess in the latter. The upper end of this hard tube is provided with a beveled sharp edgeA adapted to indent the end of' the gage nipple (35 surrounding the passage through the latter and to make a tight joint therewith. llf'hen the lock nut is set up against the liant wheel hub, the latter is iirinly connected with the block G-l, and said block can then be rotated by the hand wheel. in attaching a gage to the tester, the nipple or stem ot' the is set into the socket of the block 6l and pressed down until its end bears against the steel tube 6T. rlhe block and hand wheel are thereby mover. together downwardly against the yielding resistance ci' spring 61. Then the hand wheel is rotated, and the block Glis screwed up on the gage nipple G5 until the lip 60 bears against The threaded connection between the hand wheel and block 6l permits an adjustment of the block to accommodate variations in the length and diameter of s insure that the gage stem will )e oressec a `ainst tube G7 when the block isen as as the lip 30 andi'lange 57 i' lock nut 5S merely maintains i engages are strong, it is possible to press the gage nipple against the tube G7 with great torceyso that the tube may indent the nipple and produce a leakage-tight joint. v

An alternative constru tion .tor obtaining a tight joint is shown in Fig. 9. Here the tube 6.7 instead ot' having a sharp edge is provided with a thimble which projects from its end and is adapter'. to enter the bore in the nipple. rii'ound this thimble and seated in a recess in the end of the tube is a washer The washer is compressed when the gage nipple is drawn against the end of the tube (3? as already described, and thereby makes a leakage-tight joint. The only purpose et' the thimble is to conline the washer and prevent it from being crowded by the pressure to which it is subjected so far across the passage as to obstruct the latter. Fig. piston adapted to be substituted for the piston lll shown in Figs. 3 and el. This piston 16 is made of a size to lit the enlarged chamber 13 in the top cylinder S. @n the upper end of piston 16 there is provided a screw thread7 and adjacent to such thread a shoulder 70, by which the weight table 9"* is positioned and secured. ln the use of the apparatus it is sometimes necessary, for purposes which l will presently name, to substitute the piston 16 for the piston 16, and rice `versa, and in making such substitution it necessary only to remove the cap 1-1 itt' the piston 1G is in place, removing with it the contained piston, and to substitute therefor the other piston 1G, or the reverse.

In the operation of the tester it is necessary that the pistons 16, 20, and 21 should slide in their respective cylinders freely under the pressure produced by movement of the screw plunger 4 8, and that these pistons should not stick. Sticking of the pistons 9,0 and 21 would be a serious matter and would vitiate the results obtained by the tester. Accordingly l provide a mechanism for keeping these pistons in continuous rotation whenever the tester is in use, thereby applying sufticient :torce to overcome any tendency to stick which there might be after the pistons 'had remained stationary for some length of time, and applying this force in such a way that it does not ai'l'ect the dead pressures employed in the operation of the tester. Said mechanism comprises an upright shaft 71 having a spur pinion 72 and a horizontal shaft 73 having a crank 74 and 8 shows an alternative form oitl a beveled gear` which meshes lwith a bevel pinion 76 von the shaft 71. Shaft 73 is suplported by a bracket 75a which is secured upon the sideof cylinder 7, and the shaft 71 has a pivot bearing at its lower 'end in a hardened block 77 set into the base 1, while its upper end is 'contained in a bearing in the base plate 6, through which the shaft passes. The gear pinion 72 meshes with the spur teeth 24 of the shaft 23 and has a long face, as shown in Figs. 1 and 2, the length ofv its face being suilicient to permit the weight to move lup and down, that is, axially, through a considerable ydistance without bringing its teeth out of mesh with those of the pinion. On shaft 71 is also secured a y wheel 78, the purpose ofv which is to regulate the speed of this rotating mechanism, and allow it to be turned slowly but continuously and at a substantially uniform f speed, even though the motive power is applied manually to the crank 74. It will be understood that when the crank 74 is frotated,.the shaft 71 is also rotated with its fly wheel and pinion, and that through the engagement of the latter with the teeth 24, the weight 23 and attached piston 20' are also rotated. In Vits rotation the pin 28 of theweight engages the dog 29 of piston 21 and rotates the last named piston also..

Thus by applying an occasional impulse to the crank while the tester is beingused, 'the pistons may be kept in continuous rotation suiliciently to overcome any tendency to stick which there might be if the pistons were allowed to become stationary. As the rotating impulse is applied in a direction perpendicular to the axis of the pistons, while the testing pressures are applied to the latter only in the direction of their axis, it is evident that the force producing rotation in no wise increases vor diminishes the force exerted through the tester by the wei hts.

I aving fully described the details of construction of the yparticular embodiment of my invention herein illustrated, I will now describe the manner in which the tester operates in use, and will explain the fundamental principles of my invention involved in this construction.

In the condition prior to use, the 'screw plunger 48 is withdrawn, and the chambers 30, 22 and passages 81, 32 are vfilled with the pressure transmitting fluid, andfso also are the chamber 19 and the chamber 12. When no ga'geis connected to the cylinder, the pressure transmitting fluid, being unconlined, allows the pistons and weights to gravitate to their lowest possible'positions, where they arrest against theV frame parts of the tester. Now assuming that a gage is connected with the tester and made ltight as described, and that the'needwle valve '36 and three-way cock 34 are closed so that there lmeans of the handles 52 until suticient of the fluid is displaced from the chamber 30 into the cylinder chamber -22 to lift piston 21-7 weight 23 and piston20, and by the upward movement of the latter Ito displace the fluid ifn chamber 19 sufIicien-tly to lift piston 16 and the weights supported'thereby. In other words, theoper'ator turns the handles of the v"plunger until the weight table 9 is raised slightly and oats. The pressure thus produced in the transmitting luid'is indicated bythe pointer of the gage, and is measured bythe weights resting on the piston 16, when multiplied by factorsdetermiied according to the 'design of the machine. The pressure applied by the pistonl on the piston 20 is multiplied bythe larger area of that piston, and is added to the dead weight of the piston 2'0 and weight 23. This weight is then concentrated on thesmall piston 21, to produce 'a very high unit pressure.

Without limiting my inrentn to any' particular dimensions', I may say that in a tester which hasbeen built, the weight of the piston 16"and table 9 is ten ounces and that the piston 16 is one-sixteenth of a square inch' in area. The piston 20 has a transverse area of one square inch, hence the fluid pressure acting upon its upper end is multiplied sixteen times land becomes ten pounds.A The weight of the piston 2O and weight 23'together equals ten pounds, and this being added to the :pressure acting on the piston 20, produces a total pressure of twenty pounds on the piston 21. The latter piston is one-tenth of a square inch in transverse area, whereby 'the pressure applied by it to the gage, in terms of pressures per square inch is multipliedV ten times' and becomes tw'o hundred pounds. Thus in a tester of the particular design referred to a weight of ten iounces in the top cylinder acting through the intermediate pistons produces a pressure'of one hundred pounds per square linch lat the gage. If the intermediate pistcns and the transmissionV fluid resting on piston 20y had 4no weight whatever the indication at the gage produced by the ten ounce weight would be one hundred pounds, but as such intermediate pistons and this riluid'necessarily have some weight,V

loc

made of a definite known amount so as to lbe l isc der, it is possible to test gages up to exceedingly high pressure by the direct action in a vertical line or' Calibrating or testing weights 10 which are not prohibitively heavy or bulky. The foregoing igures are given for illustration, and they may be varied in any particular tester Without in any degree departing from my invention. Generally stated the principle of my invention is the multiplication of dead weight pressure by interposed, fluid-operated and operating members, whatever the dimensions and proportions of such members may be, and whatever the product of such multiplication in consequence may be in a testing apparatus adapted to test the calibration 01' pressure gages. Expressing the idea by a general formula regardless of actual quantities, the unit pressure produced at the gage by a weight represented as A, is

AXRXN,

where R is the ratio between the areas of the piston 20 and the piston 16, and N is the reciprocal of the area of the pis-` ton 21 in terms of the unit pressure area vith reference towhich the gage is calibrated.` lhen it is desired to calibrate cr test a gage for smaller pressures than the least produced through this multiplication, that is, in a tester of the sort here described, for pressures less than one hundred and sixty times the pressure of the weights acting through the plunger 16, the by-pass 33 is called into operation through the opening of needle valve l11 and the placing ofvcoclr 3-1 in position ier connecting the by-pass pipe with passage 35. Then the pressure produced by the piston 16 is transmitted through the by-pass, past the multiplving piston, to the gage. This equalizes the pressures in chambers 19 and 22. The piston 20, being larger than piston 21, is

forced down until the weight 23 is at rest on n the tcp of cylinder 2 and, when the area of piston 16 is one-sixteenth of a square inch, the unit pressure prcducedY at the gage is then only sixteen times the gravity pressure of the weights. That is, the factor N ot the above formula is omitted, and the factor l becomes the reciprocal of the area of piston 16 in terms of the unit pressure area. For calibrating still lower pressures, the piston 16a is substituted for the piston 16, and having' Aa larger pressure area than that of pistonv16, it produces a less pressure at the gage. Assuming that the area of piston 16"L is ten times that of piston 16, then the pressurespreduced at the gage are only one and six-tenths times the weight of piston 16, or

in other words, one-tenth of the pressures produced by piston 16, when the dead weights are the same. Still another mode of using the tester whereby even smaller readings by the use of the same weights may be obtained, is to connect the gage at the by the weight of the pistons 20 and 21 and the weight 23. 1n this way the dead weight pressures produced are reduced in being transmitted to the gage, and the unit pressures indicated by the latter' are only onetenth as great as the pressures of the weights. Thus with the tester designed as herein illustrated and described gage readings may be produced by the direct action of weights equal respectively to one-tenth, 1.6 times, sixteen times, and one hundred and sixty times the actual pressures produced by the weights, or in other words the tester enables the pressures of the weights to be modified by four different factors in being transmitted to the gage. lThe change from the direct action of piston 16 to the indirect action through the pistons 2O and 21 and vice versa is made with the utmost ease and despatch by respectively opening or closing the needle valve 41.

The chambers 12 and 19 constitute mutually communicating chambers, in which are the disconnected pistons 16 and 20 one of which acts on, and the other of which is `acted upon by, the pressure transmitting fluid; while the chamber 22 is in communication with the gage, but not with the chambers 12 and 19, and as concerns these two chambers, may be considered a non-communicating chamber. The pistons 20 and 21 are mechanically connected pistons operating respectively in the non-communicating chambers 19 and 22. When the top cylinder and gage are transposed for the purpose of producing pressures at the gage less than those directly produced by the weights, then the chambers 12 and 22 are the mutually communicating chambers, the chamber 19 is the one in communication with the gage and non-communicating as respects the other chambers, and the pistons 2O and 21 are still mechanically connected pistons in respectively non-communicating chambers.

In the foregoing description and in certain of the following claims I have used the terms cylinder7 in description of the members 2, 7 and 8, and the term piston in description of the members 16, 2O and 21. I desire to state that these terms are used as terms of description and not of limitation, because it is immaterial for all purposes except one whether the cylinder and piston are geometrically cylindrical in form or not, and whether the pistons fit the interior chambers in the several cylinders, or not. The only purpose for which cylindrical form of the chambers and pistons is required, is that of permitting rotation to prevent sticking, and for all' other lpurposes these elements may have any other shape. Accordingly it is to be understood that in all the claims Where I refer to cylinders and pistons, I do not intend to limit my invention to elements having geometrically cylindrical shapes or to pistons fitting the chambers in vwhich they operate, but by these terms I intend to include any elements however formed Which are capable in a broad Way of accomplishing functions corresponding to those performed the elements above referred to of my apparatus'.

I claim:

l. 'A gage tester, comprising a chamber containing'transinission fluid, a Weight-aetuated piston operating in said chamber, a second piston having a dierent area from the first piston operated by such fluid, a second'chamber, a third piston operating in said chamber having a different( areaifroin4 the tivol first-naniedpistons and connected to the second piston, said second chamber f being in communication vvith'the gage to be tested.

2. A gage tester, including a plurality of chambers, VVone of which is in communication With the gagefto be tested, and all of which contain a pressure-transmitting fluid, Weight-'operated 'meansl for producing a pressure in 'one of said chambers, and intermediate means betiveen said chamber and that chamber which' is in communication with the Vgage for transmitting a'modiyfied pressure to the gage.

3. A gage tester, comprising chambers containing transmission fluid means yfor mounting a gage in 'conditionl to admit such fluid and means for applying pressure to such fluid by direct action of a Weight, and means for multiplying by a lrnoivn'factor the pressure so produced in its transmission to the gage being tested.

4. A gage tester, comprising communicating chambers of different areas containing a transmission fiuid, a Weight-actuated piston in one of said chambers, a fluid-actuatedfpistonin theV other o f said chambers, a third chamber -containing transmission fluid,Y a piston contained" in said third chamber, and mechanically voperated the secondnanied piston, the last-named chamber be; ing in communication ywith the being tested.

5.- A gage tester, including in its. construction a plurality of chambers, tivo of. Which are in mutual communication and* one of Which is separated from the said tivo chambers andfis in communi'cation4 with the gage, mechanically. connected pistons of differentareasbontained respectively non-communicating chambers, and a third,

piston of still a different areacontainedi 'in cally *conneicted the second-named piston. i i n 7, Agage tester, comprising essentially a chamber Vcontaining transmission fluid,l a. Weight-'actuated piston operating in said chamber,` a second chamber in communication With the lfirst-named chamber, second piston in said second chamber having a different area f'omvthat of the first-named piston, a third chamber ineomniunication With the gage toY be tes te da third piston operating in said third' chamber andmechanically connected `with the second-named piston, and a by-'pass from'the second tothe third chamber arranged tov transmit pressure directly from the second tothe third chamber Without causingactuation of the. second and thfdri-stQsi 8l A gage tester, comprising communicating chambers containing a pressure transmitting duid, disconnected pistons of different areas in said-Hchambers, one of said pistons being Weight actuated and the other lbeing pressed upc-n by the fluid Iin said chambers, a separate chamber in communication with the gage to be tested and containing fluid, and a lpiston acting in the last named' chamber and mechanically actuated chamber containing the Weight-actuated pifsf t0n to the ses@ 10. A' gage tester, comprising communicating chambers containing a pressure transmitting fluid, disconnected pistons ofdifferent areas inV said chambers, `one 'of said pistons being.` `veight-actuated and the other being pressedy upon bythe fluid, a separate chamber in communication. With the gage to be tested and containing fluid,a piston actingfin the last named chamber and mechanically actuated by th'e secondl of the beforeuid, disconnected pistons of diflOt' iio

named pistons and driving mechanism for moving said mechanically ccnnected pistons.

11. A gage tester, comprising communicating chambers containing a pressure' transmitting fluid, disconnected pistons of different areas'in said chambersfone of said pistons being weight actuated land the other being pressed upon by the fluid, a, separate chamber in communication with the gage to be tested and containing fluid, a piston acting in the last named chamber and mechanically actuated by the second of' the before-named pistons 'and means for displacing the pressure-transmitting fluid so as to raise the pistons.

12. A gage tester, comprising communicating chambers containing a pressure transmitting fluid, disconnected pistons of dif-Y ferent'areas inl said chambers, one of said pistons being Weight actuated and the other being pressed upon by the fluid, a separate chamber in communication with the gage to be tested and containing fluid, a piston' acting in the last named' chamber and'r mechanically actuated by the second of the before-named pistons, and ,manually actuated means acting to displace the fluid in the last named chamber so as to raise the piston therein, and thereby raise all the pistons.

13. A dead Weight gage tester comprising in combination a basev having, a portion tov which a. gage to be tested may be connected, a high pressure cylinder connected to said base, said base having a passage connecting said portion and the high pressure cylinder together, a piston insaid high pressure cylinder, an intermediate cylinder, a

second piston contained iny said intermediate cylinder and engaged with the first named piston so as to operate the latter by mechanical action, a primary cylinder inA communication With the intermediate cylinder, a Weight actuated piston operating 'in said primary cylinder to apply fluid pressure to the second named piston, and a by-pass having a valve, and arranged to transmit pressure directly from the primary cylinder toy that portion ofl the base with which the gage is connected, Without applying unbalanced pressure to either the first-namedl or the second piston.

lll. .fr gage tester comprising a cylinder containing fluid and in communication with the gage to be tested, a Weight actuated piston acting in said chamber', and mechanism for moving said piston independently of the weight-produced movement and in a direction transverse to such movement to prevent sticking of the piston.

15. A gage tester comprising a cylinder containing fluid and in communication with the gage to be tested, a Weight-actuated pis-y ton acting in said chamber, and mechanism for moving said pistonrotatably about its axis to prevent sticking of the piston in the cylinder 1,6; Agage tester comprising in its construction,v` disconnected cylinders, one of ris in communication with the gage to be tested, mechanically connected pistons in said cylinders respectively and Weight operated'means for producing pressure in the other cylinder than that ivhich is connected with the gage, a gear elementconnected to said piston and gearing meshing with said gear element for rotating said pistons to prevent sticking thereofin their cylinders.

17. A, gager tester comprising in its construction," disconnected cylinders, one of which is in communication With the gage to be tested, mechanically connected pistons in said cylinders respectively and Weight op.- erated means for producing pressure in the other cylinder than that which is connected with the gage, a gear element connected to said piston and a vrotatable shaft mounted adjacent to said element, a pinion on said shaft meshing With said gear element, and a crank connected with said shaft for rotating the same and thereby rotating said pistons` to prevent the latter from sticking in their cylinders.

18. A dead Weight gage tester comprising in its construction a base having a connector for a gage, and having a cylinder in communication, with said connector, an intermediate cylinder, mechanically connected pistons in said first-named cylinder and intermediate cylinder, a primary cylinder connected With said intermediate cylinder and containing a Weight-actuated piston,

said primary cylinder being adapted to be disconnected from said intermediate cylinder and to be connected With the gage connector, and the gage to be tested being connectible, in, place of the primary cylinder, With the intermediate cylinder, whereby to transmit reduced pressures from the Weight to the gage.

19. A connection for attaching a gage to a tester, comprising a tube, a nut rotatably mounted on said tube, a nipple engaged .vith said nut having a threaded socket to receive the nipple of' the gage, and an extension tube passing from the first named tube through said nipple and constructed to make a fluid tight connection with the end of the gage nipple.

20, A connection for attaching a gage to a testing machine comprising a tube connected With the testing machine and having a tubular extension ol diameter intermediate the external and internal diameters of the gage nipple, a nut rotatably mounted on such tube extending bevond the end thereof to an extent less than said tubular extension, a block surrounding said tubular extension having an internally threaded socket to receive the nipple of the gagegand having an externally threaded neck to engage said nut, said block being engageable with the gage nipple and being movable by said nut to bring the gage nipple into fluid tight connection with the tubular extension.

E21; In a dead weight gage tester, a pressure cylinder having communicating chambers of different diameters, a piston' fitting the chamber of smaller diameter, means for transmitting pressure from said chamber to a gage to be tested, a cap extendingover the end of the chamber of larger diameter, through which cap the piston rod passes, and a stop on the piston rod contained in the chamber of larger diameter and adapted to engage said cap for preventing displace ment of the piston from the chamber.

22. ln a dead weight gage tester, a cylin der having a chamber adapted to contain fiuid, a weight-actuated piston litting said chamber and extending out from the end thereof, and complemental stops mounted upon said cylinder and piston respectively for preventing displacement ofthe piston from the chamber.

23. A gage tester comprising a fluid-containing chamber, a weight-actuated piston at the end of said chamber, intermediate chambers and pistons operated by the fluid displaced from the first-named chamber and adapted to transmit fluid pressure to the gage to be tested, a by-pass for transmitting pressure fluid directly from the first-named chamber to the gage, and a valve opening and shutting off said by-pass, said valve be-Y ing adapted tol withstand severe' fluid pressures and comprising a relatively massive casing having a passage through it, said passage being offset between its ends to provide a valve seat, a needle valve having a tapered end, fitting said seat and said needle valve passing through a side of the casing, a gland threaded into the side of the casing surrounding the needle valve and having an internal thread with which a thread on the needle valve meshes and packing contained between the end of said valve, the needle valve and the adjacent parts of the valve casing. 1

24. A tester comprising a chamber adapted to. contain iluid and having provisions for connection with a gage, a weightattuati piston exposed te the pressure el fluid in said chamber, a screw plunger ex-` plunger, and packing material interposedbe tween said gland and washer.

2o. ln a dead weight gagetester, a chamber adapted to contain fluid and having communication with the gage to be tested,

26. In a dead weight gage tester, a chamber adapted to contain fluid, means for making communication from said chamber to a gage to be tested, a weightimpelled piston exposed to the pressure of fluid in said chamber, a screw plunger entering said chamber for applying pressure to the fluid therein,

said chamber having a shoulder surrounding said plunger, and means for packing the Y entrance to the chamber through which Vthe plungerl passes, said packing means comprising a gland threaded into the entrancey to the chamber and in threaded mesh with the screw plunger, a washer surrounding the plunger and abutting against said shoulder, and' packing Ymaterial contained between said washer and said gland.

Q7. in a dead weight gage tester, a chamf ber adapted to contain fluid, means for making communication from said chamber to a gage to be tested, a weight impelled piston exposed to the pressure of fluid in said chamber, a screw plunger entering said chamber for applying pressure to the fluid therein, said chamber having a shoulder surrounding entrance to the chamber through which the plunger passes, said packing means comprising a gland threaded into the entrance ysaid plunger, and means for packing the.

to the chamber and in threaded mesh with the screw plunger, a washer surrounding the plunger and abutting against said shoulder, vand packing material contained between said washer and said gland, said plunger having a head or stop within the chamber adapted i to contact with said washer and prevent complete withdrawal of the plungerV from the chamber. y y n 28. A dead weight gage testing apparatus, comprising a weight impelled piston,

a chamber adapted to contain fluid in which area from the first named piston exposed to the pressure of the fluid on which the-first piston acts, a third piston mechanically actuated by the second piston, a chamber in which said third piston operates, containing a pressure-transmitting fluid, and means fol connecting a gage in fluid-receiving communication with the last-named chamber.

p 29. A dead weight gage testingY Vapparatus, comprising a weight impelled piston' a chamber adapted to contain fluid in whicli said piston acts, a second piston of different area from the first-named piston exposed to means for applying pressure to the fluid the pressure of the fluid on which the first contained in the last-named chamber. 1o piston acts, athird piston machanicallyactu- In testimony whereof I have aiXed my ated by the second piston, a chamber in signature, in presence of tWo Witnesses.

which said third piston operates, containing FRANK H. HOPKINS.

a pressure-transmitting fluid, means for con- Witnesses:

necting a gage in iuid-receiving eommuni- ARTHUR I-I. BROWN,

cation With the last-named chamber, and P. N. PEZZETTI.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

